2 * ASCII/ANSI art decoder
3 * Copyright (c) 2010 Peter Ross <pross@xvid.org>
5 * This file is part of Libav.
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * ASCII/ANSI art decoder
27 #include "libavutil/common.h"
28 #include "libavutil/frame.h"
29 #include "libavutil/lfg.h"
34 #define ATTR_BOLD 0x01 /**< Bold/Bright-foreground (mode 1) */
35 #define ATTR_FAINT 0x02 /**< Faint (mode 2) */
36 #define ATTR_UNDERLINE 0x08 /**< Underline (mode 4) */
37 #define ATTR_BLINK 0x10 /**< Blink/Bright-background (mode 5) */
38 #define ATTR_REVERSE 0x40 /**< Reverse (mode 7) */
39 #define ATTR_CONCEALED 0x80 /**< Concealed (mode 8) */
41 #define DEFAULT_FG_COLOR 7 /**< CGA color index */
42 #define DEFAULT_BG_COLOR 0
43 #define DEFAULT_SCREEN_MODE 3 /**< 80x25 */
45 #define FONT_WIDTH 8 /**< Font width */
47 /** map ansi color index to cga palette index */
48 static const uint8_t ansi_to_cga[16] = {
49 0, 4, 2, 6, 1, 5, 3, 7, 8, 12, 10, 14, 9, 13, 11, 15
54 int x; /**< x cursor position (pixels) */
55 int y; /**< y cursor position (pixels) */
56 int sx; /**< saved x cursor position (pixels) */
57 int sy; /**< saved y cursor position (pixels) */
58 const uint8_t* font; /**< font */
59 int font_height; /**< font height */
60 int attributes; /**< attribute flags */
61 int fg; /**< foreground color */
62 int bg; /**< background color */
64 /* ansi parser state machine */
72 int args[MAX_NB_ARGS];
73 int nb_args; /**< number of arguments (may exceed MAX_NB_ARGS) */
76 static av_cold int decode_init(AVCodecContext *avctx)
78 AnsiContext *s = avctx->priv_data;
79 avctx->pix_fmt = AV_PIX_FMT_PAL8;
81 s->frame = av_frame_alloc();
83 return AVERROR(ENOMEM);
86 s->font = ff_vga16_font;
88 s->fg = DEFAULT_FG_COLOR;
89 s->bg = DEFAULT_BG_COLOR;
91 if (!avctx->width || !avctx->height) {
92 int ret = ff_set_dimensions(avctx, 80 << 3, 25 << 4);
99 static void hscroll(AVCodecContext *avctx)
101 AnsiContext *s = avctx->priv_data;
104 if (s->y < avctx->height - s->font_height) {
105 s->y += s->font_height;
110 for (; i < avctx->height - s->font_height; i++)
111 memcpy(s->frame->data[0] + i * s->frame->linesize[0],
112 s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0],
114 for (; i < avctx->height; i++)
115 memset(s->frame->data[0] + i * s->frame->linesize[0],
116 DEFAULT_BG_COLOR, avctx->width);
119 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
121 AnsiContext *s = avctx->priv_data;
123 for (i = 0; i < s->font_height; i++)
124 memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset,
125 DEFAULT_BG_COLOR, xlength);
128 static void erase_screen(AVCodecContext *avctx)
130 AnsiContext *s = avctx->priv_data;
132 for (i = 0; i < avctx->height; i++)
133 memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width);
138 * Draw character to screen
140 static void draw_char(AVCodecContext *avctx, int c)
142 AnsiContext *s = avctx->priv_data;
146 if ((s->attributes & ATTR_BOLD))
148 if ((s->attributes & ATTR_BLINK))
150 if ((s->attributes & ATTR_REVERSE))
152 if ((s->attributes & ATTR_CONCEALED))
154 ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x,
155 s->frame->linesize[0], s->font, s->font_height, c, fg, bg);
157 if (s->x >= avctx->width) {
164 * Execute ANSI escape code
165 * @return 0 on success, negative on error
167 static int execute_code(AVCodecContext * avctx, int c)
169 AnsiContext *s = avctx->priv_data;
175 case 'A': //Cursor Up
176 s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
178 case 'B': //Cursor Down
179 s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
181 case 'C': //Cursor Right
182 s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH);
184 case 'D': //Cursor Left
185 s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
187 case 'H': //Cursor Position
188 case 'f': //Horizontal and Vertical Position
189 s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
190 s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0;
192 case 'h': //set creen mode
193 case 'l': //reset screen mode
195 s->args[0] = DEFAULT_SCREEN_MODE;
197 case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
198 s->font = ff_cga_font;
203 case 2: case 3: //640x400 (25 rows)
204 s->font = ff_vga16_font;
209 case 6: case 14: //640x200 (25 rows)
210 s->font = ff_cga_font;
215 case 7: //set line wrapping
217 case 15: case 16: //640x350 (43 rows)
218 s->font = ff_cga_font;
223 case 17: case 18: //640x480 (60 rows)
224 s->font = ff_cga_font;
230 avpriv_request_sample(avctx, "Unsupported screen mode");
232 if (width != 0 && height != 0 &&
233 (width != avctx->width || height != avctx->height)) {
234 av_frame_unref(s->frame);
235 ret = ff_set_dimensions(avctx, width, height);
238 ret = ff_get_buffer(avctx, s->frame, AV_GET_BUFFER_FLAG_REF);
240 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
243 s->frame->pict_type = AV_PICTURE_TYPE_I;
244 s->frame->palette_has_changed = 1;
245 memcpy(s->frame->data[1], ff_cga_palette, 16 * 4);
247 } else if (c == 'l') {
251 case 'J': //Erase in Page
252 switch (s->args[0]) {
254 erase_line(avctx, s->x, avctx->width - s->x);
255 if (s->y < avctx->height - s->font_height)
256 memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0],
257 DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]);
260 erase_line(avctx, 0, s->x);
262 memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]);
268 case 'K': //Erase in Line
271 erase_line(avctx, s->x, avctx->width - s->x);
274 erase_line(avctx, 0, s->x);
277 erase_line(avctx, 0, avctx->width);
280 case 'm': //Select Graphics Rendition
281 if (s->nb_args == 0) {
285 for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
289 s->fg = DEFAULT_FG_COLOR;
290 s->bg = DEFAULT_BG_COLOR;
291 } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
292 s->attributes |= 1 << (m - 1);
293 } else if (m >= 30 && m <= 38) {
294 s->fg = ansi_to_cga[m - 30];
295 } else if (m == 39) {
296 s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
297 } else if (m >= 40 && m <= 47) {
298 s->bg = ansi_to_cga[m - 40];
299 } else if (m == 49) {
300 s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
302 avpriv_request_sample(avctx, "Unsupported rendition parameter");
306 case 'n': //Device Status Report
307 case 'R': //report current line and column
310 case 's': //Save Cursor Position
314 case 'u': //Restore Cursor Position
315 s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH);
316 s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
319 avpriv_request_sample(avctx, "Unknown escape code");
325 static int decode_frame(AVCodecContext *avctx,
326 void *data, int *got_frame,
329 AnsiContext *s = avctx->priv_data;
330 uint8_t *buf = avpkt->data;
331 int buf_size = avpkt->size;
332 const uint8_t *buf_end = buf+buf_size;
335 ret = ff_reget_buffer(avctx, s->frame);
337 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
340 if (!avctx->frame_number) {
341 memset(s->frame->data[0], 0, avctx->height * FFABS(s->frame->linesize[0]));
342 memset(s->frame->data[1], 0, AVPALETTE_SIZE);
345 s->frame->pict_type = AV_PICTURE_TYPE_I;
346 s->frame->palette_has_changed = 1;
347 memcpy(s->frame->data[1], ff_cga_palette, 16 * 4);
349 while(buf < buf_end) {
359 s->x = FFMAX(s->x - 1, 0);
362 i = s->x / FONT_WIDTH;
363 count = ((i + 8) & ~7) - i;
364 for (i = 0; i < count; i++)
365 draw_char(avctx, ' ');
376 s->state = STATE_ESCAPE;
379 draw_char(avctx, buf[0]);
384 s->state = STATE_CODE;
388 s->state = STATE_NORMAL;
389 draw_char(avctx, 0x1B);
395 case '0': case '1': case '2': case '3': case '4':
396 case '5': case '6': case '7': case '8': case '9':
397 if (s->nb_args < MAX_NB_ARGS)
398 s->args[s->nb_args] = s->args[s->nb_args] * 10 + buf[0] - '0';
402 if (s->nb_args < MAX_NB_ARGS)
403 s->args[s->nb_args] = 0;
406 s->state = STATE_MUSIC_PREAMBLE;
412 if (s->nb_args > MAX_NB_ARGS)
413 av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
414 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args])
416 if ((ret = execute_code(avctx, buf[0])) < 0)
418 s->state = STATE_NORMAL;
421 case STATE_MUSIC_PREAMBLE:
422 if (buf[0] == 0x0E || buf[0] == 0x1B)
423 s->state = STATE_NORMAL;
424 /* ignore music data */
431 if ((ret = av_frame_ref(data, s->frame)) < 0)
436 static av_cold int decode_close(AVCodecContext *avctx)
438 AnsiContext *s = avctx->priv_data;
440 av_frame_free(&s->frame);
444 AVCodec ff_ansi_decoder = {
446 .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
447 .type = AVMEDIA_TYPE_VIDEO,
448 .id = AV_CODEC_ID_ANSI,
449 .priv_data_size = sizeof(AnsiContext),
451 .close = decode_close,
452 .decode = decode_frame,
453 .capabilities = CODEC_CAP_DR1,